More than half of new HIV-1 infections are acquired by women through intravaginal exposure. The cervico-vaginal epithelial cells lining the mucosal surfaces of the female lower genital track provide an initial defense against HIV-1 infection, but protection is incomplete. Transport of HIV-1 across this barrier is critical for HIV-1 colonization and virus dissemination. The long-term goal is to enhance anti-HIV-1 humoral immunity at the mucosal surface by local expression of anti-HIV-1 neutralizing antibodies to block epithelial cell attachment and virus entry. The safety profile, low immunogenecity and rapid advancement of other AAV based gene therapies into human clinical trials makes it a feasible approach to HIV-1 prevention. During my fellowship, I will investigate whether stable adeno-associated virus (AAV)-neutralizing human antibody gene transfer to endocervical, ectocervical and vaginal epithelial cells can provide durable protection against HIV-1. Specifically, I will 1) Determine the AAV serotype (1-9) that provides optimal gene transfer to these cells without toxicity;2) Isolate new neutralizing human anti-syndecan 1 and anti-syndecan 2 antibodies from a 27 billion member phage display library and test their abilities to block attachment of HIV-1 to human primary cervico-vaginal epithelial cells;and construct a Virus Inhibitory Peptide (VIRIP)-Fc fusion protein and test its ability to inhibit infection by blocking viral fusion. The anti-syndecan antibodies and VIRIP-Fc proteins will be tested for inhibition of virus internalization and transcytosis across the cervico- vaginal epithelial cells and infectivity of the transcytosed virus particles in vitro. 3) Determine if stable AAV- mediated gene transfer can be achieved in the lower genital track of mice with durable intravaginal secretion of neutralizing titers of human anti-syndecan antibodies and VIRIP-Fc fusion proteins. Finally, intravaginal AAV-anti-syndecan and AAV-VIRIP-Fc gene transfer studies followed by intravaginal HIV-1 challenge in a human hematopoietic stem cell-engrafted mice model will provide an experimental test of this novel hypothesis. The success of this novel approach could be advanced to non-human primate studies, and support prophylactic vaccine research with the potential to advance AIDS prophylactic vaccine strategies. PULBIC HEALTH RELEVANCE: HIV-1 infections are acquired most often through sexual contact and more than half of new infections are acquired by women through intravaginal HIV exposure. I propose to develop a genetic vaccine that when delivered to the mucosal surface of the cervix and vagina to allow the lining cells to stably produce human antibodies that block HIV-1 attachment and infection. A protective genetic vaccine delivered to the female lower genital track could dramatically slow the spread of HIV/AIDS.